Screen.



T. J. STURTEVANT.

SCREEN. I APPLICATION rILEDnBoA. 9, 1912 1,087,994. Patented Feb.34%;914

2 SHEETS-SHEET 1.

T. J. STURTEVANT.

SCREEN.

APPLICATION PILBD 9150.9, 1912.y

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Patented Feb. 24, ,1914.

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UNrrED vsrrnrns PATENT OFFICE.

THOMAS JOSEPH STURTEVANT, OIE" WELLESLEY, MASSACHUSETTS, ASSIGNOR ToSTURTEVANT MILL COMPANY, A CORPORATION OF MAINE.

SCREEN.

Specification of Letters Patent.

Patented Feb. 24, 1914.

i Application led December 9,1512. Serial No. 735,760.

l tors, and more particularly separators of that class intended forscreening finely pulverized material such as Portland cement and thelike, and in which the screen or screens are jarred by percussiveaction.

The invention has for its object to provide convenient means forelastically holding the wineJ mesh screen clothing of a screen underproper tension, Y and the present improvements preferably comprisevmeans whereby the tension of the screen clothing may be adjusted so asto compensate for any stretch- 'ing which may resultfrom use.

In carrying the invention into effect the wire mesh screen clothing issecured in any suitable manner to a rigid frame, preferably of wood, andthe said wire mesh clothing is held taut by a stretching frame whichbears against the said wire mesh clothing inside of the boundaries ofthe inner walls of the screen frame, and which stretching frame iselastically and preferably adjustably mounted on or supported from thescreen frame. The stretching frame is preferabl of such size as to bearagainst the wire clothI clothing at the parts thereof adjacent to thescreen frame, and the said screen frame and stretching frame are bothpreferably of rectangular form so that the stretching pressure may beapplied'to the wire mesh clothing in such a manner as to serve tostretch the latter in two directions at right angles to each other.

In the accompanying drawings Figure 1 is a partly broken, out plan viewof a screen embodying the present invention, and Fig. 2 is a sectionthereof on line 2 2 of Fig. 1. Fig. 3 is a partly broken out plan viewof a somewhat different form of the invention from that shown in Figs. 1and 2, and Fig. 4 is a section on line 4 4, Fig. 3. Fig. 5 is a sectionsimilar to Fig. 4 but illustrating a slightly different form of theinvention from that shown in the other views.

Referring to Figs. 1 and 2, 12 denotes a rigid screen frame which ispreferably .of rectangular form and-to which is attached, in anysuitable manner, as by tacks or other- Wise, wiremesh screen clothing13. The stretching frame 14 is also preferably of rectangular form, andis provided with a' raised edge part or rib 15 somewhat smaller in sizethan the interior of the stretching fr ame 12 so as to be adapted tobear on the wire mesh screen clothing Within the planes or boundaries ofthe inner Walls of said screen frame and near the said Walls. Thestretching frame 14 is a separate or inde pendent frame and is attachedto the screen frame by means of screws 16 which are provided withcollars 17 between which and the screen frame 13 are interposedcoilsprings 18 so that by the. action of said screws and coil springs therib 15 or stretching portion of the stretching frame may be elasticallyforced against the wire mesh vscreen clothing 13 to hold the latter tautand under proper tension. By adjusting the screw 16 and therebyincreasing or diminishing the. stress of the coil springs 18 the wiremesh screen clothing may be elastically held under any desired ydegreeof tension.

Owing tothe fact that the ribbed portion of the stretching frame is ofrectangular form and bears upon the wire mesh screen clothing both nearthe sides and the ends of the screen frame, the stretching pressure ofthe stretching frame will be applied to the screen clothing at a rightangle to the latter, and will also be so applied to said screen clothingas to stretch the screen clothing both sidewise and lengthwise of thescreen frame or screen.

In the form of the invention shown in Figs. 3 and 4, the stretchingframe 19 is mounted on spring brackets 20 interposed between thescreenframe 12 and winged nuts 21 on the threaded portions of bolts 22passing through the screen frame l2; so that by turning the said nuts onthe said bolts the said stretching frame may be forced with any desiredpressure against the wire mesh screen clothing 13.

ln the construction shown in Fig. 5 the spring brackets 20 to which thestretching frame 19 is attached, are bolted to the screen frame 12, thesaid stretching frame thus bearing elastically against the screenclothing 13.

From the foregoing it will be apparent that the invention provides meansfor automatically or elastically holding the wire mesh clothing of ascreen under proper tension by means of a stretching trame the pressureof which is applied to the said screen clothing at a right angle to thelatter; and it Will also be apparent that the said pressure is exertedagainst the screen clothing in two directions at right angles to eachother so as to hold the saine taut both side- Wise and endwise ofthescreen. It will also be understood that by adjusting theelastically-applied stretching pressure of the stretching frame eitherby means ot' the screws 16 shown in Figs. l and Q, or the winged nutsQ1, shoun in Figs. E and l, the stretching pressure may be varied orregulated as may be desired; so that any looseness or slackness of thewire mesh screen clothing occasioned by wear maybe readily taken uporcompensated for.

The invention is particularly applicable to separators in which thescreens are jarrcd by percussive action, in thatl the yieldingly orelastically supported stretching frame will tend to absorb percussiveshocks, more or less, in such a manneras to avoid or lessen any tendencyof injury to the screen clothing. j The stretching frame, or the ribbedor stretching portion 15 thereof, as shown in Figs. 1 and 2, Will beadapted to telescope more or less 'within the screen trame 12, Whenstretching pressure is applied; and the same is true of the stretchingframe shown in Fig. 5.

The invention is not to be understood as limited to the details hereinshown, as the same may be varied widely within the province ofmechanical skill without departing from the essence of the invention.

Having thus described my invention I claim and desire to secure byLetters Patent:

1. A screen comprising a rigid screen frame and screen clothingattached. thereto, combined with a yieldingly-supported lstretchingframe independent of said screen frame and arranged to bear against saidscreen clothing Within and closely adjacent to the inner Walls of thesaid screen frame, and means for varying the stretching pressure of saidstretchingl frame.

2. A screen comprising a rigid screen frame and screen clothing attachedthereto, combined With an independent, yieldinglysupported stretchingrame arranged to bear against said screen clothing Within and closelyadjacent to all the inner walls ofthe said screen frame, said stretchingJframe being so constructed as to apply its stretching pressure to thesaid screen clothing in two directions at right angles to each other soas to hold said screen clothing under tension both lengthwise andsidewise of the screen.

3. The combination with a rectangular screen frame andscreen clothingattachedl thereto, of an independent, rectangular, yieldingly-supportedstretching frame arranged to bear against said screen clothing closelyadjacent to and Within all of the inner walls ot said screen frame.

4. The combination with a. rectangular screen frame and screen clothingattached thereto, of an independent, rectangular, `rieldingly-supportedstretching frame arranged to press against said screen clothing adjacentto and within the inner walls of said screen frame, and means forvarying the stretch-ing pressure of said stretching traine.

The combination with a screen frame provided with screen clothing, of anindependent stretching trame elastically connected with said screenframe and having a stretching portion bearing against said screenclothing within and adjacent to the inner walls of said screen frame andserving to Yforce said clothing inward within the said inner walls.

G. In a screen, the Acombination With a screen traine provided withscreen clothing securely attached thereto, of an independent stretchingframe yieldingly' supported on and adapted to telescope more or lessWithin said screen frame and to bear against the said screen clothingWithin and adjacent to the inner Walls ot said screen frame, and meansfor forcing said stretching frame 100 against said screen clothing.

7. In a screen, the combination with a screen traine provided withscreen clothing securely attached thereto, of an independent stretchingtrame yieldingly supported on 105 and adapted to telesco e more or lessWithin said screen frame an to bear against the said screen clothingWithin and adjacent to the inner Walls of said screen frame, means forforcing said stretching frame against said screen clothing, and meansfor regulating or adjusting the pressure of the said stretching frameagainst said screen clothin i In testimony whereof I affix my signature,in presence of two witnesses.

THOMAS JOSEPH STURTEVANT. Witnesses:

W. V. ELLIS, H. A. ToMLINsoN.

